Arcjet alternatives

Tools that do what Arcjet does, found by what they say they do rather than by shelf. Among the equally alike, the most used come first. Each line says how it differs from Arcjet.

Read 2026-10-21 · Arcjet itself: From $25/mo

With a free plan or free to use: Lakera, Constellation Gate AI, SovereignShield, Wardstone, PromptGuard, zn, AI Security Guard, Lumo by Proton.

10 alternativesUnlike Arcjet

#1
Lakera Security
Detects and prevents prompt injection attacks, data leakage, and jailbreaks in AI applications with real-time threat detection.
Free planMore widely used
2.9k
Active
Free plan
1993
#2
Constellation Gate AI Security
Intercepts AI requests to block prompt injection attacks, reduce token usage by 20%, and audit all traffic.
Free planAlso: Monitoring
2
Active
From $20/user/mo
#3
SovereignShield Security
Blocks prompt injection attacks and prevents unauthorized actions in AI agent requests before they reach the model.
Free planMore widely used
24 linking domains
Active
From $5 once
#4
Kalpit Labs Security
Detects and blocks prompt injection, jailbreaks, and data leaks in LLM applications in real time.
More widely used
Emerging
Maintained
#5
Wardstone Security
Detects prompt injection attacks, jailbreaks, harmful content, and PII leakage in LLM inputs and outputs.
Free planCosts more
298
Active
From $199/mo
#6
PromptGuard Security
Inspects requests to LLM applications and blocks prompt injection, jailbreak attempts, and personally identifiable information leaks.
Free planCosts more
12
Active
From $99/mo
#7
zn Security
Blocks prompt injection attacks on AI agents with deterministic rules running locally in 0.1ms.
Free planCheaper
Emerging
Active
From $19/mo
#8
AI Security Guard Security
Detects malicious packages, scans prompts for injection attacks, and monitors agent runtime security.
Free planAlso: Agents
675
Maintained
Free
2025
#9
Barndoor AI Security
Routes AI model and agent requests through access controls, data-loss prevention and audit logging before they reach the model.
More widely used
6.5k
Active
Contact sales
#10
Lumo by Proton Security
Provides encrypted email, calendar, cloud storage, password manager and VPN under one Proton account, with the Lumo chat assistant as an add-on.
Free planAlso: Chat assistant
3.4M
Active
Free plan
2014

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How this list is made: the words Arcjet is described with (what it does, for whom, what it is used for) are matched against every tool in the Atlas. A tool on the same shelf, or doing the same kind of work, counts for a little more. Nothing here is paid for.